But today, May 29, at the US District Court in the southern district of New York in Manhattan, he and his defence team from Kramer, Levin, Naftalis & Frankel LLP are fighting the fight of his life. Gary P Naftalis, the law firm's co-chair, is one of America's top white-collar defence lawyers.

"Gupta is lucky to have Naftalis," says Stephen Gillers, professor of law at New York University, who has known both Naftalis and the presiding judge, Jed S Rakoff, for years. Gupta needs all the luck he can get.

In a six-count indictment, the US Department of Justice charged that Gupta "joined in an agreement or understanding" with Galleon Group's Raj Rajaratnan, who is serving an 11-year prison sentence and was fined $156 million, "to disclose inside information about Goldman Sachs, P&G, and the JM Smucker Company."

Prosecutors named Michael Cardillo and Ian Horowitz co-conspirators. Cardillo, a former Galleon trader, pleaded guilty of criminal charges last year. Horowitz is not indicted. The names of four others have been withheld.

The case smacks a bit of Sherlock Holmes. For example, the indictment states that on September 23, 2008, Gupta took part via telephone in a special meeting of the Goldman board, which approved a $5 billion investment from Berkshire Hathaway. Approximately 16 seconds after that call, Gupta's assistant called Rajaratnam and connected Gupta to the call. Four minutes later at 3:58 pm, two minutes before close of market, Galleon Tech Funds bought approximately 2,17,200 shares of Goldman common stock for approximately $27 million.

Legal experts say although such evidence is not direct, it's powerful and compelling. "The evidence against him is unusually strong—direct phone contact almost immediately after a crucial board meeting, followed by an immediate trade," says Lynn A Stout, professor at Cornell Law School.

"It is possible to prove a criminal case by circumstantial evidence. Success is dependent on the prosecutor's ability to present a series of facts that have only one reasonable interpretation—namely, that the defendant, in fact, gave inside information so that someone else could trade on it," says Thomas Lee Hazen, professor at the University of North Carolina (Chapel Hill) School of Law.

And that's exactly what assistant US attorneys Reed Brodsky and Richard Craig Tarlowe, appearing for US attorney Preet Bharara, are trying to construct. Their task is to prove beyond a reasonable doubt to the 12-member federal jury of New Yorkers, who will determine Gupta's fate, that it was he who tipped off Rajaratnam.

Naftalis is doing everything he can to convince the jury that the government has put the wrong man on trial. The defence strategy thus far is four-fold.

One: Plant doubt in the minds of the jury that Rajaratnam could have had any number of inside sources. Two: Thoroughly discredit certain witnesses as liars. Three: Weaken the prosecution's evidence as hearsay. Four: Given Gupta's personal net worth of $84 million, argue that he would not have risked his reputation for financial gains.

In court, silver-haired Naftalis, 70, has an understated demeanour. But it would be a mistake to underestimate him. This is a man who managed to persuade the US government not to file criminal charges against Salomon Brothers for US Treasury auction bidding practices, and against securities firm Kidder, Peabody in connection to insider trading.

But the last few years have been rough for individuals facing white-collar charges. Bloomberg reported that since August 2009, 59 people pleaded guilty or were convicted out of a total of 66 who were charged with insider tipping. So far no one was found to be not-guilty and some cases are pending.

Naftalis has a soft but forceful way of poking holes. During a cross-examination of Jon Moeller, chief financial officer at P&G, he made Moeller acknowledge that several people besides Gupta, including employees at P&G and Smucker and their lawyers, were aware, prior to the announcement, about P&G's impending sale of Folgers to Smucker.

Raj's brother RK Rajaratnam on June 2, 2008, purchased 75,000 shares in Smucker. Naftalis said in court that there was nothing aberrational about the trade. He was head of Galleon's consumer products team.